The present invention relates to an inkjet recording apparatus for recording an image by causing an inkjet recording head to discharge an ink supplied from an ink cartridge through an ink channel as ink droplets, and a control method of the inkjet recording apparatus.
Conventionally, there is known a so-called inkjet type image recording device that records an image on recording paper by discharging ink droplets from a recording head onto the recording paper. Such an inkjet recording apparatus employs a structure for supplying an ink from an ink chamber storing the ink to the recording head through a predetermined ink channel. When the ink in the ink chamber is completely used by image recording, the ink chamber is refilled with the ink, or the ink chamber is replaced with an ink chamber filled with the ink. In the later case, there may be a method in which the empty ink chamber is replaced together with the recording head, and a method in which the ink chamber is constructed as an ink cartridge separately from the recording head and only the ink cartridge is replaced. In order to decrease the ink replacement cost, the method of replacing only the ink cartridge is more advantageous.
The ink cartridge is provided with an ink supply opening for supplying an ink from an ink chamber, and the ink supply opening is sealed with a seal member such as rubber. When the ink cartridge is mounted in a cartridge mounting section of the inkjet recording apparatus, an ink needle provided in the cartridge mounting section goes through the seal member, and the ink in the ink chamber is guided to the ink channel through the ink needle.
When replacing the ink cartridge, there may be a problem that the air enters into the ink needle. More specifically, since the point of the ink needle is released to the atmosphere by removing the ink cartridge from the cartridge mounting section, the liquid surface in the ink needle changes due to various factors. Then, when a new ink cartridge is mounted in the cartridge mounting section, the ink needle goes through the seal member of the new ink cartridge and enters into the ink chamber filled with the ink, but the air that has entered the ink needle during this series of replacement operations remains. The remaining air functions as a core to grow an air bubble in the ink channel, and the air bubble produced in the ink channel may cause an ink discharge defect in the recording head.
Therefore, in order to remove the air remaining in the ink needle, there were proposed means for pushing the air out of the ink needle toward the ink chamber, and means for removing the air bubble in the ink channel by sucking the ink in the ink channel from the recording head (see Japanese Patent Applications Laid-Open No. 07-89081 (1995) and No. 2004-136502).